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v ELECTRIC ARG LAMP. Y No. 562,313. 4 Pa, 1entedJune16, 1896.

z'fzw'e.' 1 1 22M/72306:' l www.; @liver ily/@wijze f MW @ymm UNITED STATES ATENT OEEicE.

OLIVER S. LYFORD, JR., OF CHICAGO, ILLINOIS, ASSIGNOR TO THE SIEMENS da I'IALSKE ELECTRIC COMPANY OF AMERICA, OE SAME PLACE.

ELECTRIC-ARC LAMP.

SPECIFICATION forming part of Letters Patent No. 562,313, dated June 16, 1896.

Application filed April 6, 1896. Serial No. 586,287. (No model.)

To all whom t may concern.:

Be it known that I, OLIVER S. LYEORD, Jr. a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Arc-Lamps, (Case No. 90,) of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to an improvement in arc-lamps, the object thereof being to provide means for arresting the combustion of the lamp-carbons, while avoiding the disadvantages attendant upon maintaining` the arc in a more or less complete vacuum.

Arcelamps have hitherto been constructed with this end in view, "wherein the are was maintained in a globe normally sealed from the external air, but provided with valves designed to equalize differences of pressure upon the exterior and interior of said globe. As it is not necessary to maintain the arc in a vacu um in order to secure practically the same results as to lengthening the life of lampcarbons and like desirable results can be obtained by permitting sufficient communication between the interior and the exterior of the arc-chamber to allow at all times the equalization of pressure, I have provided for the arc-chamber a port which is sealed by a porous or fibrous diaphragm adapted to permit the entrance of air or the exit of gases v when the pressure upon-the interior and extratin g a lamp provided with my device.

terior are unequal, and which practically seals the said chamber from the external air at all other times.

The device of the present application wil-l be more readily understood by reference to the accompanying drawings, in whichn Figure l is a view, partly in section,- illus- Fig. 2 shows in detail the porous diaphragm closing the port.

Like letters refer to like parts throughout both views.

The arc-lamp a of the usual construction is iitted with a globe b, of glass or semitransparent material, which completely incloses the arc c and lower portion of the frame d. To the upper portion of the globe is sealed the casing e, which serves to completely close the arc-chamber f, except for the port g, preferably situated above the arcin the casing e. Port gis provided for the equalization of the internal and external pressures upon the globe without `permitting the entrance within the globe of sufficient oxygen to materially increase the combustion of the carbons, the said port being closed by a diaphragm 7L of any suitable porous or fibrous material, such as asbestos or felt, through which the air or gases will necessarily have to pass to either enter or leave the arc-chamber. Thus, ordinarily, there will be no appreciable circulation of air through the diaphragm and, the oxygen being excluded from the arc-chamber, the combustion of the carbons will be almost entirely arrested. By thus employing a simpler constructiomwherein a diaphragm is provided for equalizing the pressures upon `the exterior and interior of the arc-chamber7 all difficulties attendant upon the liability of an equalizing-valve to become fast in its seat, remain open, or otherwise fail to respond to variations in pressure,are avoided.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. In an arc-lamp, the combination with an inclosing chamber for the carbon electrodes normally sealed from the external air, of a porous or fibrous diaphragm for securing the equalization of any substantial difference be tween the external and internal pressures upon the walls of the said inclosing chamber, substantially as described.

2. In a sealed casing for an electric-arc lamp, the combination with a port connecting the interior thereof with the external air, of a porous or fibrous diaphragm normally closing the said port while permitting the passage of air or gas freely through the said port when influenced by a difference in the external and internal pressures upon said casing, substantially as described.

3. In an arc-lamp, the combination with the arc, of a globe and casing forming an arcchamber, a port provided in said casing, and a porous or fibrous diaphragm normally sealing the said port, preventing the passage of air or gas, adapted freely to permit their pas- IOO sage to equalize any material differences between the pressure Within the interior of the arc-chamber and the atmospheric pressure, substantially as described.

4. In an arc-la1np, the combination with the globe b inclosing the are, of the easing` e sealed to the globe and forming` with said globe an ardehainber, port g provided in the arc-chamber, and porous or iibrous diaphragm 7L closing said port and normally maintaining the arc-chamber sealed from the external air,

but adapted to permit exit of gases freni Within or the entrance of air from Without as the pressure Within the are-Chamber is greater or less than the pressure of the external air, substantially as described.

In Witness whereof I hereunto subscribe in y nanie this 1st day of April, A. D. 1896.

OLIVER S. IYFORD, JR. Witnesses:

CHARLES A. BROWN, A. L. LAWRENCE. 

